An amphibious vehicle includes, for instance, an engine, a land traveling device including a crawler or tires, a water traveling device including a water jet or a propeller, and a power distribution device which distributes power outputted from the engine between the land traveling device and the water traveling device.
Further, the amphibious vehicle disclosed in Patent Document 1 includes a vehicle controller for controlling an engine-output divider (power distribution device), a vehicle-speed sensor, and an engine rotation-torque sensor. The amphibious vehicle can be operated under three different modes: land mode, water mode, and intermediate mode. In the intermediate mode, the power of the engine is distributed between the land traveling device and the water traveling device. Further, in the intermediate mode, the output of the engine is increased if slippage of the land traveling device is detected on the basis of the vehicle speed and the engine rotation torque. Accordingly, the power of the water propelling device is increased, and the vehicle speed that has decreased due to the slippage increases and becomes stable.